Liquid level control



Nov. 24, 1953 Q HANNEY 2,660,193

LIQUID LEVEL CONTROL Filed Aug. 5, 1949 INVENTOR ANGUS F. HANNEY BY ATTORNEYS Patented Nov. 24, 1953 UNITED STATES NT OFFICE LIQUID LEVEL CONTROL Application August 5, 1949, Serial No. 108,697

1 Claim. 1

This invention relates to apparatus for controlling the level of liquid in or admitted to a reservoir or container.

One object of the invention is to provide an im-, proved control apparatus or system for the purpose'which is'quite simple and involves only a few parts which are not likely to get out of order in service; which is easy to install, adjust and operate; which is self cleaning in the sense that the liquid under control ordinarily does not enter any pipe or conduit of the control system; and which is sensitive to variations in the head or level of liquid in the reservoir and thus is especially accurate in operation.

Further objects of the invention in part are obvious and in part will appear more in detail hereinafter.

In the drawings, Fig. 1 represents somewhat diagrammatically one embodiment of apparatus involving the invention;

Fig. 2 is a detail side elevation of'one form of apparatus suitable for variably adjusting or predetermining the. liquid level to be secured and maintained;

Fig. 3 is an end elevation from the left in Fig. 2;

Figs. 4 and 5 are side elevations, corresponding to Fig. 2, illustrating other arrangements for variably adjustingthe liquid level; and

Fig. 6 is a detail section on the line 6-6, Fig. 5.

While the apparatus or control system of the present invention is capable of use for a wide variety of industrial purposes, for convenience'and in no sense of limitation the drawings illustrate its use for producing, controlling and maintaining 7 any predetermined level of the detergent liquid in a washing or dry cleaning machine. This machine is conventionally shown as including an outer tub or container I 0 in which is rotatably mounted the usual perforate work holding cylinder or drum H. Liquid is supplied to the con-1 leaving the circuit sensitive to automatic opentainer by way of'supply pipe 12 in which isva control valve l3, normally. biased to closed posi-l tion, the stem! 4 of which is actuated to'open the a suitable support. This lever i5 is connected to the movable core of a solenoid coil lllaterjreierred to.

operatively associated with a switch or other means for controlling theliquid supplyvalve by valve by elevation of lever I5 pivoted at lfiupon tions in the liquid level, in the container for the 3 purpose of producing and maintaining any predetermined or desired level therein.

As shown, the control system includes a pipe or conduit it having one end 19 open at a low level in the liquid in container l0, said pipe being connected at its opposite end, as at 20, to a suitable source of supply of a gas, such as air, under pressure, and intermediate its ends to a suitable pressure operated prime mover, such as the expanding and contracting bellows 2|. Bellows 2|, through a motiontransmitting member 22, operates a normally closed switch 23, member 22 being biased, as by compression spring 24,

to move downward, or in opposition to member 2|,

in Fig.1. a i V While any suitable form of mechanical or other operating connections may be interposed between member 22 and valve [3, the drawings show an electrical system including the solenoid l1 and switch 23 before referred to. 1 The electrical system also includes a normally open push button starting switch 25,. When this is closed a circuit is completed from Ll, by wire 25, holding coil 21, switch 25 and switch 23 to L2. Energization of coil 2? closes switch completing a circuit through wires 29, 35, in parallel with coil 21, through solenoid ll, thus energizing said solenoid and opening valve l3. Switch Zilserves as a maintaining switch for coils 21, I1 enabling the push button 25 to be released,

ing of switch 23. V

Assuming that with the container It empty of liquid the system has been put into operation by depressing push button 25 name manner just describedopen valve I 3 will admit detergent liquid, such as water or a dry cleaning fluid, to

container it until a liquid level is reached in said container such as to build up back pressure in bel lows 2i sufiicient to overcome the rare-adjusted I or pre-selected opposing resistance of spring 24" and thus open switch 23 This opens the' main circuit and deenergizes both of coils 21, I1, allowing maintaining switch 23 to open and valve I3 -to I and duringstand-by periods as well, some gas I under pressure is constantly emitted in a series of bubbles from the open end I9 of pipe l8. Consequently, the liquid in the container never enters pipe l8, the inner channel of which is always dry and never gets a chance to collect a deposit of dirt or any ingredient of the detergent solution and clog or choke"; Each timdthepushbutton is depressed- .momentari-ly, the operator knows with certainty that the container will be filled with liquid to the desired level and no higher.

The system shown in Fig. 1 is capable of ad, justment to vary the desired level of liquid inany suitable manner, preferably by: the use of. a motion transmitting member betweenprime. mover 2| and valve [3 adjustable to various de grees of response to operation of the prime mover. Fig. 2 shows one such arrangement.

Here the prime mover, bellows 2 is spaced: some distance from the actuatingistem of switch 23. In the interveningspaceis" mounteda rotatable tu-r ret,-marl:ed. generally 3+, in which. are mounted a series of rods or pl-ungers- 22., each biasedto the leftby; a-compression spring. 2%,. the. strength .of eachaspring being variable by adjustment of nuts- 32, Theturret as-aw-hole is-carriedby a shait 33 rotatably adjustable manually-by knob- 34. to bring: any-fiche of the rode into axial. alinement with bellows 2:1. and switch 23,. a ball: latch: tfi-zholdingtheassembly in the selected. position; Thus-theresistance opposing expansion of: prime-mover. 2i

maybe varied, with. consequent variation. inthe selectedlevel of liquid to be produced-.-

Block 36,. 'whichvsupports bellows it, here is provided with-two: needle valves iii, 3%, the first for-adjusting. theflow tdpi-pe l8 and bubble tube I 9-, and. the second for further: adjustment oi the flovwtathebellows 2 t,- so that surges will not prematurely' actuate the; control...

Figs. and 6 show an equivalent arrangement, butiwh-ich. employs but a single spring variable as to strength. Here, thesingle-motiontransmitting. rod- 22 carries-one-springifl the-strength of which maybe: varied. by slidable adjustment, along rod: 22, of collar 39. For this purpose said collar isprovided.with..pins 40 (Fig. 6) entering. recesses in the upper arm 41. of a pivoted lever, the lower arm-'42 of which may be' adjusted. to and held in several: positions by screws 43 threaded: into a head lllcarried by rotatable shaftd5 Four screws are shown, giving'four different positions of the lever and four diiterent values of compression of spring 24:

hr all; of the forms so far described, assuming that-lost:motionbetweerr the opposite ends of; rod 22 andetheswitch and bellows,;respectively, is-so small as to be negligible, expansion of thebellows: up? to the time of switch operation is always the same fixedamount and may be. disregarded. It is the variable compression-ct the springwhichrequires variableuse. in back press-ureand thussensitizes the: control-system to various levels oil liquid;

Fig; 4' shows. an: arrangement which takes. ad vantage of thefact that'there isa certain amount of springiness in'the bellows itself; which varies with the amount or length of bellows'expansion, so that" different liquidlevels-may be secured.

Here, the bellows 2'! is again spaced from the switch; but the intervening space is occupied by'a sloping disc cam lfi mountedon a shaft 41 rotatable by knob 48. By rotating said shaft any peripheral portion of the cam' may be brought into position between the bellows and switch, thus varying the amount o1 free expansion of thebelresistance is always a fixed factor.)

4 lows before the cam is contacted. A spring 24 backs up the cam and opposes its advance.

The result is that when switch operation occurs, it happens because sufficient back pressure has been built up to overcome two factors, first, the resistance of the bellows itself to expansion up to the point of contact with the cam and, second, the resistance of the spring duringmotion of the cam suflicient to operate the switch. (Switch The first factor. isvariable. The second is fixed or constant. Consequently, by adjusting the cam to various positions, diiierent liquid levels may be secured.

Under certain conditions or in certain instances, the-push button switch 25, Fig. l, is not essential and may be omitted, in which case the circuit remains permanently closed at that point. Such anarrangement may be used, for example, when it is desired to maintain any particular desired' level of liquid in" the-reservoir or container to which it is being supplied. One: arrangement of that kind, for example, is illustrated-in. a prior application for Dry Cleaning System; Serial Number- 716,676; filed February 16 1949, by Edward A.

Creswick, and-which has become Patent: No.

2,630,694 dated: March: 10;.-1-953,.-andiowned.by the same interests. as the present application, to.

which Creswick. application access-may be had if desirable or necessary."

In: such an arrangement, omitting. switch 25 and" assuming the circuit from Ll to L2? to be energized; if. the'level of liquid in: the reservoir is below that indicated in Fig. 1-,.the switch 23, which now is the onlyccntrollerior the circuits. is closed; Accordinglyicoir lli is energized-andthe valve !3 is open. Liquid flows into the contain'er until-.it reachesthe level indicated, where the: backpressure" built up; in bellows 25! becomes great enough to actuate and open switch 23, thus deenergizing'coi'h Ht andfper'mitt'ing valve l3'to close. Whenever the'leve'h of liquid. for any reason.

falls below that indicated, .switclr 23' again is" closed and the valve is opened and remainsopen' until the desired level is again: reachedi- The effect is a sort ofg'overn'or' action; constantly maintaining a desired level of liquid;

All forms are unusually simple and yet sen sitive-. The apparatus also lends itself admirably" to those situations in whichthe control parts desirably are located at some distance from the valve mechanism or container.

Other advantages of the invention will be apparent. to those skilled in theart.

What I. claim is In combination, in a. system of the character described; a chambered container for liquid,. a liquid. supply pipe communicating therewith. and

provided with. a normally closed. control. valve, a.

solenoidflhavi'ng a movable, armature. adapted. when said solenoid is. energizedfto become effective on: said valve tocause opening movementthereof," electrical circuit means. which, when having one portion adjacent said switch and another portion adjacent said bellows, said motion transmitting means consisting of a rotatable turret carrying a plurality of plungers, any one of said plungers being effective individually to actuate said switch when rotated to registry with said switch and with said bellows, whereby expanding motion of said bellows moves a plunger in said motion transmitting member to abut said switch and cause opening movement thereof so as to break said circuit, each said plunger being provided with spring means normally biasing the plunger away from said switch, the spring tension for each plunger differing from that of the other plungers for preadjustably varying the resistance to motion transmission of said motion transmitting member while the pressure from said gas References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,936,049 De Mers Nov. 21, 1932 2,302,923 Zimarik Nov. 24, 1942 2,305,154 Gilbert Dec. 15, 1942 2,457,874 Davis Jan. 4, 1949 2,518,484 Matthews Aug. 15, 1950 2,592,314 Morton Apr. 28, 1952 FOREIGN PATENTS Number Country Date 327,474 Great Britain Apr. 10, 1930 

